东北漫岗黑土区浅沟侵蚀发育特征

Growth Characteristics of Ephemeral Gully in Rolling Hills of Black Soils in Northeast China

东北黑土区是中国重要商品粮基地之一，沟道恶性扩张，已成为导致该区土地退化主要原因之一。利用全球定位系统和传统方法测量浅沟形态参数，结合地理信息系统（GIS）平台计算流域尺度的沟蚀现状，分析东北黑土区浅沟侵蚀发育特征，并对比分析其与黄土高原浅沟侵蚀发生的地貌因子之间的异同。研究表明，研究区浅沟分布密度0．56—0．93km／km^2，年侵蚀模数达到118～199m^3／km^2，浅沟破坏面积占流域面积比例达0．11％～0．19％，浅沟沟壑密度已经达到中度和强度侵蚀，处于快速发展时期；研究区浅沟的临界汇水面积大于黄土高原，分布的临界坡度小于黄土高原，这主要由黑土区坡长坡缓的特点决定。

With the deepen understanding of soil erosion at spatial scale, gully erosion has been attracted more interest than ever. The black soils in Northeast China is one of the important bases for food supplies, but now the soil erosion, especially the fast expansion of gully erosion, has been one of the most important reasons for soil degradation. This paper made use of Global Positioning System （GPS） to measure the shape characteristics of ephemeral gully（ EG）, the platform of Geographical Information System to calculate the status of EG erosion, and analysis the geomorphic factors to determine the occurrence of EG erosion. The results show that the distribution density of EG is 0.56-0.93 km/km^2, its annual erosion modulus is between 118 m^3/km^2 and 199 m^3/km^2, and the proportion of the destroyed area by EG come up to 01 11% -0.19% of the watershed area. These indicated that gully density has reached middle and intensity degree erosion, being in rapid growth stage. It was also found that the threshold catchment area of EG in the study area is larger than that in the Loess Plateau, whereas the threshold slope smaller than that in the Loess Plateau. Meantime, the analyses indicated that the volume of ephemeral gully is determined mostly by its length that is mostly determined by the length of watershed. This means that mostly the length of the watershed determines the volume of ephemeral gully, which undoubtedly provides a referred thought for the construction of gully model.